Acylated hydrocarbon succinates and uses thereof

ABSTRACT

ACYLATED HYDROCARBON SUCCINATES AND DERIVATIVES THEREOF, FORMED BY (1) REACTING A HYDROCARBON WITH A MALEIC COMPOUND OR A DERIVATIVE THEREOF UNDER FREE RADICAL CONDITIONS TO YIELD A HYDROCARBON SUCCINATE AND THEN (2) REACTING THE HYDROCARBON SUCCINATE WITH A POLYAMINE TO FORM AN ACYLATED PRODUCT, I.E. AMIDES, IMIDES, AMIDEIMIDES, ETCL; AND TO THE USES OF THESE ACYLATED HYDROCARBON SUCCINATES, FOR EXAMPLE AS ANTIFOULANTS TO INHIBIT DEPOSIT FORMATION IN HIGH TEMPERATURE HYDROCARBON SYSTEMS SUCH AS IN REFINERIES, ETC.

United States Patent 3,585,123 ACYLATED HYDROCARBON SUCCINATES AND USES THEREOF Richard L. Godar and Michael I. Naiman, St. Louis, Mo., assignors to Petrolite Corporation, Wilmington, Del. N0 Drawing. Filed Nov. 18, 1968, Ser. No. 776,808

Int. Cl. Cg 9/16; C08f 3/70 US. Cl. 20848 10 Claims ABSTRACT OF THE DISCLOSURE Acylated hydrocarbon succinates and derivatives thereof, formed by (1) reacting a hydrocarbon with a maleic compound or a derivative thereof under free radical conditions to yield a hydrocarbon succinate and then (2) reacting the hydrocarbon succinate with a polyamine to form an acylated product, i.e. amides, imides, amideimides, etc.; and to the uses of these acylated hydrocarbon succinates, for example as antifoulants to inhibit deposit formation in high temperature hydrocarbon systems such as in refineries, etc.

This invention relates to the acylated hydrocarbon succinates and derivatives thereof, formed by (1) reacting a hydrocarbon with a maleic compound or a derivative thereof under free radical conditions to yield a hydrocarbon succinate and then (2) reacting the hydrocarbon succinate with a polyamine to form an acylated product, i.e. amides, imides, amide-imides, etc.; and to the uses of these acylated hydrocarbon succinates, for example as anti-foulants to inhibit deposit formation in high temperature hydrocarbon systems such as in refineries, etc.

The hydrocarbon succinates are illustrated by the following idealized formulae where R is a hydrocarbon moiety, preferably alkyl:

where n is, for example 1-5, or even 25 or more in certain instances.

The hydrocarbon succinates may also be a mixture of one or more of the above formulae.

Stated another way, the hydrocarbon moiety may have one or more maleic units attached thereto; said maleic units may be attached at one or more positions on the hydrocarbon moiety, may be attached directly to the hydrocarbon moiety or to one or more other maleic molecules, etc.

The term hydrocarbon succinate relates to the product formed by the action of a hydrocarbon with a maleic anhydride, or an equivalent or a derivative thereof by a free radical mechanism. It also includes derivatives of hydrocarbon succinates.

The term maleic compound relates to maleic anhydride, maleic acid, maleic type anhydrides or acids, esters and other derivatives thereof.

Any suitable hydrocarbon can be employed in preparing the hydrocarbon succinates.

In general, these hydrocarbons have an average of over about 20 carbons, but preferably over about 35 carbons per molecule, such as from 4550 and in some instances as high as -200 or more. Where the hydrocarbons are of a lower molecular weight, they may be blended with a higher molecular weight material to give this average. The preferred M.W. is about 600-700.

The hydrocarbon unit is preferably alkyl, and may be straight chain or branched. It may also have other groups such as cycloaliphatic, aryl, etc. groups attached to the alkyl chain.

In the preferred embodiment the hydrocarbons are alkyl and because of the economics involved are generally of petroleum origin, for example petrolatums, waxes, etc.

Because of its commercial importance, maleic anhydride is employed to illustrate this invention. Examples of other acids or anhydrides which may be reacted include citraconic acid, ethylmaleic acid, glutaconic acid, itaconic acid, methylitaconic acid, etc. The term hydrocarbon succinates and maleic compound includes these acids, anhydrides, esters and other derivatives.

We prepare the hydrocarbon succinates by reacting a hydrocarbon with maleic anhydride under free radical forming conditions. In one embodiment, the hydrocarbon, maleic anhydride and a peroxide are reacted at a temperature sufiiciently high to promote free radical formation. Since heat promotes free radical formation, a

temperature sufficiently high to promote the decomposition of the peroxide, without causing decomposition of reactants and products, is employed. Depending on the peroxide, temperatures of about 100-250 C., such as about to 225, for example about 15 to 215, but preferably about to 200, are employed. The temperature should be sufficiently high to keep all reactants in solution or in a molten state.

In the case of di-tert-butyl peroxide the best yields are obtained in the ranges of about 100 to 250 C., but preferably about 170 to 200 C.

Reaction times will depend on various factors such as for example on the particular reactants, reaction conditions, etc. A reaction time sufficient to effect the desired degree of reaction completion is employed. Ordinarily, reaction times of from about 0.5 to 6 hours, such as about 1 to 5 hours, for example about 1.5 to 4.5 hours, but preferably about 2 to 4 hours are employed. Shorter or longer times may be employed to push the reaction to the desired degree of completion depending on various factors, such as reactants, conditions, peroxides, etc.

Any suitable free-radical producing agent capable of forming reactive sites can be employed. These include peroxides, hydroperoxides, etc., for example benzoyl peroxide, acetyl peroxide, 2,4-dichlorobenzoyl peroxide, tertbutyl peroxide, tert-butyl hydroperoxide, methyl benzyl hydroperoxide, cumene hydroperoxide, peracetic acid, tert-butylpermaleic acid, lauryl peroxide, methyl ethyl ketone peroxide, dicumyl peroxide, di-tert-butyl diperphthalate, tert-butyl peracetate, and the like.

Other sources of free radicals besides peroxides can also be employed, for example high energy ionizing irradiation, etc., cobalt in conjunction with hydroperoxides, inorganic peroxy compounds such as persulfates, hydrogen peroxide, etc., azo compounds of the general formula 3 such as azobenzene, azomethane, azobisisobutyronitrile, etc., acyl-aryl nitrosoamides such as nitrosoamides such as nitrosoanilide, etc.

The hydrocarbon succinates can be prepared by the process described in US. Pat. 3,030,387 which is by reference incorporated into this application. Said US. Pat. 3,030,- 387, issued on Apr. 17, 1962, is illustrated by claim 9 which states:

A process for the preparation of alkyl hydrocarbon and cycloalkyl hydrocarbon substituted succinic acid anhydrides which comprises reacting one mole of maleic anhydride with more than one mole of hydrocarbon selected from the group consisting of alkyl and cycloalkyl hydrocarbons of from 6 to 32 carbon atoms at a temperature above 100 C. and in the presence of a catalytic amount of di-tertiary-butyl peroxide.

In one embodiment maleic anhydride and the peroxide, preferably as a solution, are added to molten well-stirred hydrocarbon and the reaction allowed to react to completion. The product is precipitated by pouring into a liquid in which the desired product is insoluble, and the by-products are soluble, such as methanol, and the wax separated therefrom by any suitable means such as by filtration, etc. Thereafter the product is washed with methanol and collected by filtration.

In another embodiment, the hydrocarbon-maleic halfester is converted to the anhydride in situ.

The hydrocarbon succinates are then employed to acylate polyamines for example as presented by the following Polyamines may also be employed to form imides or Corresponding compounds are also formed from hydroxyl amines as illustrated below. In the case of the hydroxyl amine, n is preferably 2-4, but most prefer- The polyamines employed include those of the following formula:

where n is for example 1-10 or greater, where A is a and m is for example 210 or greater. These include the following:

CH3 H NHzCHzCHzCHzNHz Other examples include the following alkylated polyamines for example of the formula I l RN-AN H where the Rs are H or a substituted group, such as cycloalkyl, alkyl, alkenyl, alkynyl, aryl, etc. The preferable type is of the formula H, ete.

NH2, etc.

Aromatic polyamines can also be employed, for example:

etc. or substituted derivatives thereof for example, alkyl, alkoxy, halo, etc. derivatives.

Thus, any polyamines capable of reaction, whether aliphatic, cyclo-aliphatic, aromatic, heterocyclic, etc., can be employed.

In addition, one may employ polyfunctional compounds having different reacting groups, for example both alcohol and amino groups such as al'aknol amines, aromatic hydroxy amines, etc.

such as where A is (1) (CH such as where x is 1-10 or greater,

substituted derivatives thereof, etc.

(3) Cycloaliphatic, etc.

Typical examples include alkanol amines, ethanol amine, propanol amine, butanol amine, decanol amine,

etc.

CHz-OH NH OH, glycerolamine :LJH-NHQ, etc.

R-CH- N CH2 CHQNHZ The following examples are presented by way of iliustration and not of limitation.

EXAMPLE 1A Forty-four pounds of molten hydrocarbon, M.W. 675,

(29.5 moles) are charged to the reactor and heated to 205 C. A mixture of 17.6 pounds of isopropyl maleate (50.5 moles) and 2.2 pounds of di-t-butyl peroxide were added over a six hour period With the temperature maintained at 205 -216 C. Then the solution is stirred onehalf hour at 215 C. Unreacted maleic anhydride was re- 1 The hydrocarbon is a petrolatum.

moved under vacuum. The solution was cooled to 110 C. and 21 pounds of aromatic solvent were added. Sixtynine and one-half pounds of product were obtained.

EXAMPLE 1B and other more complex products.

USE AS ANTIFOULANTS This phase of the invention relates to a method of chemically treating hydrocarbon liquids which contact surfaces under high temperature conditions in order to inhibit, prevent and/or reduce the deposition of substances thereon.

More specifically, this phase of the invention relates to the chemical treatment of the metal surfaces in contact with petroleum hydrocarbon liquids under conditions of high temperatures whereby said liquids tend to form deposits on such metal surfaces.

In the processing of hydrocarbon liquids, particularly petroleum hydrocarbon liquids, elevated temperatures are often used in many necessary and important operations. To handle liquids at elevated temperatures, heat exchangers and the like devices are often employed to control the heat transfer rate from one operation step to another. When hydrocarbon liquids contact hot metal surfaces, there is sometimes a tendency for the liquid to decompose or undergo a chemical reaction that manifests itself in the form of deposits. These deposits may be either cokelike or they may be in the form of tenacious, soft, sticky sludges which adhere to hot surfaces. Adherence of deposits, rather than deposit-formation itself is the essence of the problem, in contrast to fuel storage where residue in the oil itself creates the problem.

The problem is well recognized in the art-note Petroleum Products Handbook, Guthrie (McGraw-Hill, 1960), pp. 1-13, US. Pat. 2,908,824 and elsewhere.

These deposits tend to materially decrease the heat transfer capacities of the metal surfaces and hence increase operaing expenses. These deposits also require additional effort and time to remove and to restore the equipment to its original operating efficiency.

Petroleum refinery operations often encounter the above described conditions in many stages in the refining process. These deposits form on heat transfer surfaces at temperatures as low as about ZOO-225 F. and may be evidenced at temperatures as extreme as 1200 F.

It is practically impossible to prevent these deposits by coating the metal surfaces with a protective permanent coating due to the possible loss of heat transfer. In addition, the large volume of liquid that contacts such equipment increases the problem of treating metal surfaces in petroleum processing to prevent high temperature deposits.

Most of the gasoline produced today is obtained by the thermal or catalytic cracking of heavier petroleum hydrocarbon feed stocks such as light or heavy gas oils, cycle stocks, virgin or topped crude oils, lube stocks, kerosene, and kerosene-gas oil mixtures. A number of different thermal and/or catalytic cracking processes known in the petroleum industry under designations such as Fluid Process, Thermofor, Houdry, Patforming, Thermal Reforming, Viscosity-Breaking, etc., are employed for the purpose. Although these various processes differ considerably as to the precise manner in which the heavier hydrocarbon molecules are cracked to yield gasoline, they all involve the heating of the hydrocarbon feed stock to a high temperature (370l200 F.) and the passage of such heated stock, optionally mixed with a cracking catalyst, through heated tubes, reactors, converters, and tower stills. Regardless of the particular process used, the cracking operation always results in the formation of some undesirable carbonaceous material or refinery coke which adheres to the tubes, reactors, etc., of the cracking unit and lowers its efificiency, principally by impeding the flow of the feed stock there-through and the transfer of heat to or from such stock. After enough carbonaceous material has accumulated on the various parts of the cracking unit to lower its efficiency substantially, the unit must be dismantled, cleaned, and reassembled. Of course, such cleaning operations are not only tedious and costly, but result in a large proportion of down-time during which the unit is not functioning. Although the use of modern Platforming and catalytic cracking processes has reduced the amount of down-time as compared with older, strictly thermal cracking processes, the accumulation of refinery coke still presents a problem to the petroleum refining industry.

It would be advantageous if a chemical agent could be added in an extremely small amount to a hydrocarbon liquid which tends to form high temperature deposits whereby such deposits would be prevented. It would also be desirable if such a chemical would not only prevent such deposits but would also remove them without necessitating the stoppage of a given operation. It therefore becomes an object of the present invention to prevent the formation of high temperature deposits on metal surfaces by chemical means.

Another object is to furnish a chemical which when added to a hydrocarbon liquid will prevent the depositforming tendencies of said liquid when it contacts metal surfaces at elevated temperatures.

A further object is to provide a chemical treatment which will prevent the formation of high temperature deposits by petroleum hydrocarbon liquids in contact with heat transfer equipment.

Yet another object is to furnish a chemical treatment capable of being combined with a thermally unstable, deposit-forming liquid whereby said liquid will not form deposits upon metal surfaces at elevated temperatures.

Still another object is to provide a chemical treatment which will remove high temperature deposits from metal surfaces of petroleum refining equipment without the necessity of stopping the operations of such equipment. Other objects will appear hereinafter.

In accomplishing these objects in accordance with the invention it has been found that new and improved results in preventing, inhibiting and/or reducing the formation of deposits from petroleum hydrocarbon liquids during the processing thereof at elevated temperatures, particularly at temperatures Within the range of about ZOO-225 F. to 1200 F., are obtained by adding to, preferably by dissolving or dispersing in the hydrocarbon liquid, the anti-foulant compositions of this invention.

The anti-fouling additive can be employed in refining crude petroleum as Well as in the treatment of any component thereof which are exposed to high temperatures including the light distillates, for example light naphthas, intermediate naphthas, heavy naphthas, etc.; middle distillates, for example kerosene, gas oil, etc.; distillate lube oil stocks, for example, white oil, saturating oil, light lube oil, medium lube oil, heavy lube oil, and the like.

In addition, the additive can be employed with other hydrocarbons such as xylene, benzene, purified hydrocarbon compounds, etc. In addition, they can be employed under certain conditions with non-hydrocarbons, such as alcohols, phenols, etc. For example, they can be employed in a toluene extraction tower and stripper which process comprises mixing phenol and toluene in an extraction whereby phenol extracts impurities from toluene and the rafiinate is subsequently removed. Thereafter the mixture is sent to a stripper where the toluene is removed from the phenol by distillation. The remaining phenol is recycled to the extractor for further use. The system is operated over a wide temperature range for example 230-425 F. Deposits in the phenol circuit cause the loss of excessive amounts of phenol. It can be used in heat transfer units used in a furfurol extraction process processing for ex ample, intermediate distillates, parafiin distillates, decanted oil, vacuum cylinder stock, deasphalted cylinder stock, etc.

The amount of anti-fouling agent required in th1s 1nvention is subject to wide variation but in general very effective results have been obtained by adding relatively minute amounts of the antifouling agent to the hydrocarbon liquid being processed, for example, amounts may be as low as 0.5 p.p.m. in hydrocarbon liquid, for example 1 to 500 p.p.m. or higher, for example 1000 or more p.p.m., preferably 5 to 30 p.p.m., with an optimum of -20 p.p.m. In general, the upper limit is determined by the economics of the process but other factors should be taken into consideration such as whether large amounts will have any adverse efiects on present or subsequent operations. Because of the many different types of operations where hydrocarbons are heated to elevated temperatures under conditions where deposits are formed, it is difficult to give specific ranges which will be effective in all operations. The amount of agent which inhibits the formation of deposits is referred to herein as an antifouling amount. The above figures relate to p.p.m. in terms of active anti-fouling chemical not including the solvent employed.

Inasmuch as the anti-fouling agent is employed in such small amounts and it is preferable to feed them continuously or semicontinuously by means of a proportioning pump or other suitable device to the particular hydrocarbon liquid being processed or to add them in a similar manner to the apparatus in which the hydrocarbon liquid is being processed, it is desirable to incorporate the agent or a mixture of agents into a suitable solvent which will be compatible with the liquid which is to be processed. The solvent which is used to dissolve the active ingredient is also subject to some variation depending upon the solubility characteristics of the particular compound employed. In some cases, even though the active mixture is insoluble in a particular solvent, it will dissolve in a combination of solvents.

In the practice of the invention it is very desirable to start the treatment with the chemicals employed for the purpose of the invention at a higher dosage, say 20 to 50 p.p.m. or more of a composition and then gradually reduce the dosage to the point where fouling of the apparatus is just eliminated.

The invention is especially valuable where sour naphthas are being processed or where the oil being processed is a mixture containing some sour naphthas.

Examples of specific types of apparatus to which the chemical compositions of the invention can be added during petroleum processing are fractionating towers, stripping columns, debutanizers, depropanizers, deethanizers, heat exchangers, reboilers, hot product lines and other metal equipment (usually ferrous metal) which is brought into contact with the organic liquids being processed at relatively high temperatures. The invention makes it possible to extend the useful life of crude oil fractionating towers and other types of petroleum refinery equipment. It also makes it possible to provide cleaner inside surfaces resulting in better fractionation, better heat exchange in coolers, far less severe plugging and less time required for cleaning and maintenance.

The antifoulants of this invention can be employed, for example, in the operation shown in US Pat. 3,390,073 in which FIG. 1 relates to a crude preheat exchanger, FIG. 2 an alkylation reboiler unit and FIG. 3 a hydrosulfurization preheat exchanger.

TESTING PROCEDURE The conditions encountered in refinery operations are simulated by exposing petroleum products taken from various refineries to high temperature heat exchange tubes in the absence of and in the presence of the antifouling compositions of this invention.

An antifoulant testing device is used to simulate these conditions, modified so as to increase fouling tendencies. The device is essentially a small single tube, single pass heat exchanger which has a longer residence time than is norn'ially found in refinery conditions in order to accelerate fouling tendencies. The charge, with additives if any are used, is pumped through a preheater where it is heated to a constant temperature in the range of F. to F., then through the heat exchanger tube which is in a high temperature bath. Input temperature of the charge is monitored just as it enters the heat exchanger tube to be sure it remains constant. Temperature of the eflluent from the heat exchanger tube is recorded with time, with a drop in output temperature indicating that the heat exchanger tube is becoming fouled and losing efliciency. The magnitude of the temperature decrease from that at 0.5 hour is used to indicate the degree of fouling.

1 1 The results are shown in the following table: All temperatures in Table I are in F.

6. The method of claim 3 where the hydrocarbon succinate is predominately an alkyl succinate.

TABLE I.EFFLUENT TEMPERATURE, F.

Antitoulant of Example Number 1B 1 1B 1 1B 1 113 l 25 p.p.1n. 15 p.p.m. None 6 p.p.rn. None 25 ppm. None Charge type llDS charge 11 [)8 charge IIDS charge 50% #2 base, 50% #2 base, 50% #2 base,

50% light 50% light 50); light Straight run Straight run 50% #1 fuel, 50% #1 fuel, cycle cycle cycle IIDS, Feed IIDS, Feed 50% kcorsene 50% kerosene Time (his):

0.5 566. 5 567.5 563.0 552. 5 550. 7 569. 5 563. 0 1. 566. 0 567. 5 562. 6 552. 5 550. 4 567. 7 562. 5 1. 567. 5 567. 8 563. 0 552. 5 549. 9 569. 5 563. 0 2. 567. 8 567. 8 562. 6 N R 549. 1 569. 2 562. 5 2. 567. 5 567. 8 562. 0 551. 0 548. 1 569. 5 561. 8 3. 567. 5 568. 0 562. 0 551. 4 547. 9 569. 5 561. 8 3. 566. 5 567. 8 560. 3 551. 0 546. 5 569. 2 560. 3 4. 567. 2 567. 2 559. 7 550. 4 544. 5 568. 7 550. 7 4. 566. 9 566. l 559. 7 549. 9 542. 9 567. 7 559. 7 5. 566. 5 565. 8 569. 7 549. 1 540. 0 566. 8 559. 7 5. 566. 9 565. 5 558. 3 548. 8 537. 2 566. 8 558. 3

Net change 0 2 4.7 3.7 13.5 2. 7 4.7

l HDS means hydrodesulfurization. Based on weight of active material. Nora-1n each case, the input temperature to the heat exchange tube remained constant 105 F. and both input and output pressures were constant.

Having thus described our invention what we claim as new and desire to obtain by Letters Patent is:

1. A method of preventing, inhibiting and/or reducing the formation of deposits in petroleum hydrocarbon liquids at elevated temperatures within the range of about 200 F. to 1200 P. which is characterized by employing an anti-fouling amount of an antifoulant composition comprising an acylated hydrocarbon succinate formed by (1) reacting a hydrocarbon with a maleic compound under free radical forming conditions at a temperature sufficiently high to promote free radical formation without causing decomposition of reactants and products to yield a hydrocarbon succinate and then (2) reacting said hydrocarbon succinate with a polyamine to form an acylated product.

2. The method of claim 1 where the polyamine is a polyalkylene polyamine.

3. The method of claim 2 where the polyalkylene poly amine is NHZ 1-10H where A is an alkylene group having 2-3 carbons.

4. The method of claim 1 where the hydrocarbon succinate is predominately an alkyl succinate.

5. The method of claim 2 where the hydrocarbon succinate is predominately an alkyl succinate.

7. The method of claim 6 where the acylated alkyl succinate is predominately an imide.

8. The method of claim 7 where the polyamine is predominately H NHz CH2CH2N l-l0H 9. The method of claim 8 where alkyl group on the 0 DELBERT E. GANTZ, Primary Examiner G. E. SCHMITKONS, Assistant Examiner US. Cl. X.R. 

